Make VideoCapturerAndroid work on SDK level 16

talk/app/webrtc/java/android/org/webrtc/ThreadUtils.java

 /*
  * libjingle
  * Copyright 2015 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 108 matching lines @@
           result.value = callable.call();
         } catch (Exception e) {
           throw new RuntimeException("Callable threw exception: " + e);
         }
         barrier.countDown();
       }
     });
     awaitUninterruptibly(barrier);
     return result.value;
   }
+
+  /**
+   * Post |runner| to |handler| and wait for the result.
+   */
+  public static void invokeUninterruptibly(final Handler handler, final Runnable runner) {
+    final CountDownLatch barrier = new CountDownLatch(1);
+    handler.post(new Runnable() {
+      @Override public void run() {
+          runner.run();
+        barrier.countDown();
+      }
+    });
+    awaitUninterruptibly(barrier);
+  }
 }